In general, chargers from big brands (Apple, Amazon, Samsung, even Ikea) are fine because they don't want to risk damage to their brand if one were to burn down a house or something.
If your charger has a brand you've never heard of, beware!
OTOH some Ebay cables might drop it down to 500 mAh. It was a shock to me because for years I exclusively bought Ebay chargers and cables (around 1/5 of the price of Anker) thinking they would work as specified (or not at all)...
And even when you have the proper cable, you can run into the problem that the charger manufacturer thought the Apple way was the proper way.
Thing is that Apple has some very odd resistor setup on the data pins to indicate max A out of their chargers, while the USB charger spec basically says to short the data pins so that the device can sense it.
Try to charge a non-Apple device in an Apple type charger and you can get anything from full to .5A, depending on how clever the device engineers were...
There are plenty of fake chargers out there that look on the outside identical, down to the tiniest details, to Apple chargers, for example.